Epicyclic Gear Carrier Drive for Variable-Speed Power Transfer
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Solution Overview
Problem
Conventional power transfer systems in hybrid-electric aerospace power plants lack efficient variable speed capabilities and flexibility in managing rotational power across multiple sources, such as internal combustion engines and turbochargers.
Innovation Solution
An epicyclic gear system with a variable speed drive mechanism that connects directly to the carrier without a ring gear, allowing for adjustable speed ratios and rotational direction changes, enabling efficient power transfer between a turbocharger turbine and an internal combustion engine while driving accessory devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional fixed-ratio gear system is used, then the structure is simple, but the adaptability to variable speed requirements is poor
Solution Approach 1:
The patent applies a variable speed drive mechanism that allows the carrier to rotate at variable speeds relative to the input sun gear. This dynamic capability enables the system to adapt to different speed requirements by varying the rotation speed of the carrier, thereby resolving the contradiction between adaptability and structural simplicity.
Solution Approach 2:
The epicyclic gear system is designed to perform multiple functions: it can transfer power between the input sun gear and output ring gear while simultaneously providing variable speed output through the carrier. The system can also reverse rotational direction and drive multiple outputs (main output shaft and accessory drive shaft), enhancing its versatility without proportionally increasing complexity.
2Adaptability or versatility
If a variable speed drive mechanism is added, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The patent merges the variable speed drive functionality directly into the carrier of the epicyclic gear system. By integrating the variable speed drive with the existing gear structure rather than adding it as a separate subsystem, the design achieves speed variability while minimizing the increase in overall system complexity.
Solution Approach 2:
The carrier serves as an intermediary element that receives rotational input from the input sun gear and transfers it to the output ring gear at variable speeds. This intermediary role allows the system to achieve variable speed ratios without requiring complex additional mechanisms, as the carrier's variable rotation speed naturally mediates the speed transformation.
3Speed
If the carrier rotation speed is varied, then the variable speed capability is achieved, but the control complexity increases
Solution Approach 1:
The system allows the variable speed drive to directly control the carrier rotation speed without requiring complex external control mechanisms. The variable speed drive inherently provides the necessary control by varying its own rotation speed, which in turn varies the carrier speed and achieves the desired variable speed output.
4Adaptability or versatility
If accessory drives are integrated into the system, then the versatility improves, but the device complexity increases
Solution Approach 1:
The output ring gear serves multiple functions: it provides the main power output through the output shaft and simultaneously drives accessory devices through an integrated accessory drive shaft. This multi-functionality allows the system to drive multiple outputs (main output and accessories) without requiring separate, independent drive systems, thereby enhancing versatility while controlling the increase in complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides a flexible and efficient power transfer solution that maintains constant output speed despite varying input speeds, enhancing the operational range and reliability of hybrid-electric aerospace power plants.
Implementation Method 1
An input sun gear is distributed around and meshes with a first set of planet gears. A second set of planet gears is mounted to the carrier. An output sun gear is included, wherein the second set of planet gears are distributed around and mesh with the output sun gear.
Data Source
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AI summary
An epicyclic gear system (100) includes an input sun gear (102) configured to receive rotational input from a turbine (104) of a turbo charger. A first set of planet gears (106) is distributed around and meshes with the input sun gear (102). A carrier (108) holds the first set of planet gears (106) and defines a rotational axis (A) about which the carrier (108) rotates. A second set of planet gears (110) is mounted to the carrier (108). An output sun gear (112) is included, wherein the second set of planet gears (110) are distributed around and mesh with the output sun gear (112). The output sun gear (112) is configured to deliver rotational power to an internal combustion engine (114). The carrier (108) is configured to selectively be driven by a variable speed drive (116) to regulate output to the output sun gear (112) over a range of input rotational speeds of the input sun gear (102).